cup997laurent

A 993 cup has no steering assistance , I have an electric pump for mine , remember that if you want to go without assisted steering you will have to change the steering rack that is not the same . This is a most expansive part than an electric pump .
regarding the brakes the best is to find a complete 993 turbo or c4 or rs system with the high pressure pump and abs....

nothingbutgt3

For the moment I bought a used power assisted steering rack (the standard one), and a 964 steering column (without airbag) which was the same as the one installed onto the 993 RS. It would be nice not to have the power assisted steering: I remember the 911 3,2 had no p.a. steering and it wasn't uncomfortable at all.
The car is going to weight less than a 3,2, will have only a bit larger front tires, so I don't think this would be a problem.

Concerning the braking system, at first I don't think I will install the RS braking calipers and rotors, and I doubt the high pressure pump will play a role, but I am probably wrong.

Tracking the silver 993 with standard brakes with PAGID yellow on the front and Toyo R888R tyres, the braking is simply amazing: the car is going to be aroung 1180 kgs soon (fiberglass hood and few other things), the yellow one is going to be 100 kgs less, which is almost 10% less.
I understand the CUP and RSR had to race, so they just didn't need braking power, but also constant braking performance and anti fading qualities for an entire race of 20 rounds or more.

In my case, to make a perfect copy I had to install the CUP braking system, and maybe I'll do it in 10 years, but for tracking for 2 to 5 pushing rounds and then cooling down, the standard braking system I think is powerful and consistent enough...and at least 10/15 kgs lighter...ehm, lightness never hurts.

The wheels as well, the original center locking magnesium ones, aren't lighter than the OZ alleggerita that, if in the meanwhile I don't find something lighter and with same resistance, they will be the wheels of the yellow car as they are already used onto the silver one with satisfaction, I must say.

I would like to create a very performing car, not just a copy of something existed in the 95. It would be amazing to own and drive an original 993 CUP, but it is not currently in my possibilities.

I dream of the moment when the body of the car will come back fully painted from the body shop, with the glasses, the doors, the bumpers and the perfectly mounted, sparkling and winking headlights.

I Imagine when I can climb over it, surrounded everywhere by the yellow of the body shell and turn the key to start ...

In my intentions, step 1 will be something like a mystical attempt ... my nickname comes from the distant '99 when the magazine EVO nominated Car of the year the 996 GT3 mk1 ... a black devil coming off a hill and moving slightly off the ground ... .it was a 3.6 ... liquid cooled ... but the monobloc is the same. He had about 360 hp ...

If the RS / CUP / RSR are the maximum expression of the 964 monoblock in the 3.8-liter configuration, my intention, I know, it may seem absurd being aware that from a 3.8 it is easier to get horses and torque, it is to create a very powerful 3.6 naturally aspirated and air cooled engine, with a nice driveability, using most of the parts of the standard M64/05 engine, except valves, cammes, ITB, airbox, coils and engine management, just refining what's inside the motor block.

If a M64/21 Engine has more or less 286 hp, same engine perfect balanced with freer exhaust I think should be approximately, without changing anything inside around 300/305 hp (at least). This with a Motronic single throttle body management.
Adding ITB, single coils, new engine management ( I have to buy one in any case), larger and lighter valves, more aggressive cammes, maybe could add other 15/20 or maybe a bit more hp.

In the U.S. a 3,6 liter engine I know that sounds small: in Europe such a displacement is considered HUGE, and here it is not immediate at all thinking that the problem of gaining horse power must be necessairly solved adding more displacement, building something bigger: let's call it, the european (or maybe just the italian) way?!?

330 hp onto a 1080kgs car I think is worth a try...and reasonably the car will also pollute much less.

An engine designed to last as a road engine, not an engine to be serviced every 5000 km, but designed and assembled like a racing engine.

Otherway, I am considering to go immediately for step 2, adding GT3 crank shaft, rods, cylinder heads, the way RSR are made, achieving higher rpms to get more hp, but having a quick look around it is very much more expensive than the step 1.

nothingbutgt3

Little update:
I'vebeen lucky finding 2 European headlight surplus stock, the RS steering column, plus hydraulic steering rack.
I am still looking for the gearbox bearing at a reasonable price.
In the meanwhile I am considering what to do for the STEP 1 of the engine and I accidentally found 2 GT2 EVO cams for a good price, so my doubt now is: are they good/equivalent to the CUP/ RSR cams or they cannot be used since they weredesigned for a turbo engine?
I didn't want to change the engine very much with STEP 1, my intention is to use the 3,6 cylinders&pistons, but change just the top of the engine, ie valves, spring, cams, mechanic rocker arms, then adapt the ITB and the intake of '7 GT3 RS, plus new engine management and install a coil for each spark plug.

The biggest question is: is there anyone who knows if it is possible to adapt/use the normal heads with the gt2 EVO cams and/or where can I find the RSR heads again for a decent price?

If I'd be able to find the RSR heads without bleeding it could take a bit more time, but i could decide to go straight for lets say STEP 1&1/2 installing also Pankl rods and gt3 or CUP crankshaft.

If I got it right, the step 2 has to consider 3,8 cylinder&piston with deep insert for RSR valve lift, even though I already saw many talking about 4,0 liter engine, but I didn't find any info about the producer of the parts required.

Kein_Ersatz

Contact @trophy for details on the 4.0 build he did in '15, he can share lots of details. You will need GT3 internals, 4.0 parts, and new ECU/wiring harness/ITBs to start with, depending on shop/machine labor, looking at 30-50k.

trophy

More than happy to discuss what went into my build...

nothingbutgt3

Thank you very much Trophy, you don't have to say it twice: you have got mail
And thank you kein ersatz, living in Ohio, but originally from Deutschland?


Searching almost every day for used parts, I found this gearbox, described as 996 CUP MK1&MK2 gearbox: does anyone knows if changing the trasmission cover with the 993 one is possible to mount it on the 993? Or if it does exist some other way to do it.

I saw this gearbox has very long 1st gear, which is perfect for track purpose, but not just for that: since the silver 993 I am driving weights 1170kgs it is very easy to start in 2nd gear, without any without any effort for the engine or clutch, because the engine, even in a longer gear, has to push 210 kg less.



I think it is a G96.92 gearbox, because the G96.75 already has the trasmission cover similar to the one used onto the G50: hence my question, if they just change the gearbox motor mount solution, but the rest has remained the same or they re-designed most of the gearbox.

nothingbutgt3

What are the weak points in reusing the 993's crankshaft for an application that has a maximum rotation speed of 7800/8000 rpm as its target? And what if I make it rev but below 7000?
and what are the differences/advantages of using a gt3 crankshaft compared to that of the 993, if it is possible, it has a sense using it?
what about the connecting rods? Are the original ones reliable for a 7000 application onto a 3,6 liter?
Or I saw the titan Pankl rods, do they fit the 993 crank shaft?

From what I could read so far a significant improvement would be represented by a revised mechanical rocker arms layout, like for instance using the ones proposed by nine meister.

I don't understand why they don’t share at least a price lists to get an idea about the purchase price of their parts, it is all so mistery, but wasn’t it mechanic?

BY THE WAY, for the so called STEP 1 of the engine rebuild, I will have to maintain the car matching number, which means the engine block can not be machined to get the bigger Mahle cylinders and pistons.
this offers the opportunity of making a tuning of its original 3,6 liter: from what I could resemble so far, the main point of making a powerful upgrade to this engine is to make it rev higher, let’s say almost 8000 rpm.
to get to it, the 3,6 piston heads must be shaped with valves sockets like the 3,8 rsr heads are, to avoid any interference while valves open and increase valve lift, and the distribution must be lighter and adapted to operate in a reliable way with much sportier cams profiles.

Then, from what I understood so far, the 993 RSR back in 98, with electronics of 98, with material technology of 98, was able to output 410 hp in its sprint configuration and 370 in the endurance, with engine heads with 46/42 I/E doors, so why do I read posts where it is declared that RSR heads were not properly designed?
I read they should have had smaller ports, like the 964 ones, and re-designed straighter for higher velocity, less load loss.

I figured me out that, at high revs, with inlet valve open with piston going up, the air inlet inertia allows a sort of “overfeed” making enter air inside the combustion chamber winning the piston pressure, and this turbo charging alike effect is more pronounced if the speed of the air is higher and ports are smaller.
Very probably, also the inlet port/inlet valve size RATIO plays a very important role: I am not into engine build, but fluid dynamics theory is same in all engineering fields.
So the main point I think is, having a big air inlet reserve, with high speed inertia, smaller straight ports to make speed higher and remain so, to get a sort of boost effect.
IF all of that is correct, the RS and RSR heads are the worst for such an application, while the 993, varioram or not, with larger RSR machined valves and maybe also machined straighter port channels are a decent compromise: on the other side the air intake dimensioning is probably with such modified heads equally important.
I am considering of using a 997 GT3 RS air intake and ITB set up, with single coils together with an engine management able to manage it all.

My idea is to use same air intake set up for both STEP 1 and STEP 2: i cannot build 2 STEP 2, one 3,6 and the other one 3,8/3,9 liter, it doesn’t make any sense to me and it would be way tooo much expensive.

thats why I am asking myself if with all modifications described to the distribution, to cylinder heads and pistons, could it be possible to make the step 1 rev less and reuse its crank shaft and maybe connecting rods.

Thinking about crank shaft and rods to be used on a not that high revving engine: where are the limits of 993 crank shaft? Assuming I would like not to change it in the step 1, where in the bandwidth its limits would become significant?

Talat

I am pricing up a 3.8 rebuild at the moment - you need to decide what kind of power output you want. I'm quite happy with something in the 350-360bhp ballpark and so I'm told this can be achievable with a rev limit set to around 7000. At 7000 I don't need rods but I'll change them to be safe and I will retain my crank (964). If I was looking at more revs and power then I'd be looking at a GT3 crank. In the grand scheme of things, the GT3 crank and oil pump isn't that expensive - I think it's around £3k so would probably be worth the investment if going for big power.

nothingbutgt3

thank you talat,
these info are very useful: the fact is i am going to build 2 engines, STEP 1 in my idea is vitaminic engine re-build, if i can, Id like to use its original crank, crank shaft, rods,3 ,6 cilinders, heads (revising them), improved intake distribution (mechanical rocker arms, spings, larger valves if needed, etc.) plus air intake and engine management upgrade to be used on the STEP 2, which will benefit of many brand new parts.

So basically I mainly need new shaped pistons with RSR alike valve sockets, to allow bigger valve lift and opening time.

nothingbutgt3

yesterday I cleaned the plastic parts of the intake manifolds from the mud and crust: to my surprise the throttle body is still perfectly working.

Facing pieces that have been able to hold out for 4 and a half years under water, frankly the first impulse is to put them back on the car.

If I would decide to proceed Keeping the following components original:

Block
crankshaft
connecting rods
cylinders
heads
intake
throttle body
ignition

and replace with new parts:

piston top 3.6 with RSR valve slots
new camshafts (maybe ninemeister?)
new mechanical distribution (I think of ninemeister)
new valves, springs and sping hats

With this configuration the first two doubts that come to me concern the drivability at low revving: is it strictly necessary to mount also the ITB? In this case, could be an option using six trumpets?

And then: or, without ITB, such a configuration with a single throttle body, but sporty cams, is still manageable from the 272 horsepower Motronic?
Would using the Varioram's Motronic be possible and/or better?

in case it was necessary to use the ITB, at that point the control unit isn't a question anymore, because in any case it would be necessary to buy a new one to guide 6 butterflies and at that point everything is much simpler, more expensive and would look much less original.

In my opinion, opening the rear hood and seeing the engine with its black intake, looking like a 272 hp engine perfectly original from outside, on a resurrected car, has its reason.

The later on, when I will take out the engine to exchange it with the STEP 2, next to the car will proudly show itself perfectly originally looking.

Kein_Ersatz

Have not read of anyone doing a 996 Gbox in a 993, suspect there are multiple mount point alignment issues to be addressed / confirmed. Will axel shafts align? "Common" thinking seems to go with regearing and adding robustness to the G50 clutch/syncros, not swapping the Gbox out. But, someone has to be the first though ;-) I do not recall Guntherwerks or other bespoke (open checkbook) 993 builds swapping out the g50, but then someone has stuffed a v8 in a 911...

With enough money and time, engineering is possible for almost anything. The GS/billet/carbonfiber parts thread is an amazing story of what can be possible.

nothingbutgt3

I found a complete 964 engine: on this forum I read that the 964 heads, having smaller I/E ports, would be ideal for high power applications, can anyone support this?
I also read it is necessary to adapt them to the mahle 3,8/3,9 cilinders.

Concerning the crank case, is the 964 more or less appropriate/robust than that of the 993s, for applications that go towards high rpm?

For me now there are two ways:
one consist in buying the crankcase and the distribution seats, add then GT3 crank shaft, connecting rods, new heads, etc, the other one is to buy this whole 964 engine, remove the components that do not interest me, reuse the heads (after having properly worked them), sell those parts I don't need it and insert what I should put up even in the first case.
The engine in question has 36000km.

ignorance is an ugly beast

nothingbutgt3

"whoever stops is lost"
I'm already looking for a engine block 964.

In this regard, I wonder what are the differences between the codes

964.101.112/111.0R
964.101.112/111.1R
964.101.112/111.2R
964.101.112/111.3R
964.101.112/111.4R
.......

And what are the codes of a genuine 3,8 RS engine block

cobalt

If memory serves me correctly
964.101.111.1R & 964.101.111.2R are the 94 964 turbo case halves
964.101.112.1R & 964.101.112.2R are the 964 N/A case halves
964.101.111.3R & 964.101.111.4R are the 993 Turbo case halves
964.101.112.3R & 964.101.112.4R are the 993 N/A case halves

Not sure what the .0R case half is. Although these are the casting numbers and not the actual part numbers AFAIK. You might reach out to Catorce he seems to have a bunch lying around he might be able to confirm. As far as using one or the other there are a number of differences including additional filter and oiling for the 993 hydraulic lifters, The webs are different thickness IIRC the 993 has smaller webs allowing you to use more of the later 996GT3 tri-metal bearings and parts with less machining/. There are early and late 964 engines. There was a TSB issued changing the heads and cylinders to the later design with crush rings. The break off point was serial number 62M06837 for the M64.01, 5 speed engines and 62M52758 for the M64.02 tiptronic engine. These should have . different design head which was improved in the later engines preventing the warping issues.

Again Catorce probably has a spread sheet on this that would be more specific. Also locating a 993 block is probably easier than a 964 which is becoming very hard to find lately but good luck.

The 996 transaxle should bolt up to any of these cases however the nose cone is very different and mounts into the car far differently. It also would require changing the linkages and other work AFAIK. Never tried it but I would assume the nose cone would be a tight fit in a 993 tub and might need some tub modifications to make it work.

As far as the rear suspension castings I hope you don't plan to use those. They are riddled with gross corrosion to a point that they would almost certainly fail under hard driving especially with uniballs.

nothingbutgt3

Thank you Cobalt,
I am finding almost ONLY 964 blocks and only 964 complete engines, one with very low kms (30.000) almost brand new, but what is the point buying an entire engine if I only need its block?
This pictures are from the same engine block.